The imaging of objects is important in many current endeavors, including medical, pharmaceutical, and industrial investigations. Radiography, in general, is the process of producing images of opaque items by the penetration of radiation, such as gamma rays, x-rays, or charged particles, such as protons, electrons or muons. When a beam of such radiation is transmitted through a heterogeneous item, the radiation is differentially affected by its varying thickness, density and chemical composition. The radiation emerging from the items forms a radiographic image, which is formed on an image detection medium, such as onto a photographic film directly, or onto a phosphor to convert the radiation to visible light, which is then imaged.
As seen, radiography is a non-destructive method of imaging the internal features of objects. It often is used to non-destructively detect medical condition such as tuberculosis and bone fractures, and in manufacturing processes to detect defects such as voids, cracks, and porosities.
The use of high-energy protons to produce these radiographic images is a mature technology for many imaging applications. However, this type of proton radiography has several drawbacks. Among these are the reasonably low resolution of small density differences, a lack of ability to image thin objects, and the creation of a relatively high level of residual radiation in the imaged object.
The present invention solves these problems with conventional radiography by providing apparatus for the non-destructive imaging of objects using electrons as the charged particles. The electrons provide superior resolution and sensitivity in the imaging of thin objects.